Hanoi (AFP) - US Secretary of State John Kerry on Friday hailed the transformation of relations with Vietnam 20 years after ties were established, but warned Hanoi's poor rights record stood in the way of deeper bonds between the former wartime foes.
Kerry, on the last leg of a trip through the Middle East and Asia, said progress on rights issues was key to boosting the partnership between the two countries, which fought a bitter decades-long war that ended in 1975.
"We have seen some positive steps on human rights in Vietnam over the past year," Kerry said after meeting Vietnam's Foreign Minister Pham Binh Minh, pointing to the release of several high-profile prisoners of conscience, some of whom now live in exile in the United States.
But he said there was "room for improvement", urging legal reforms to remove vaguely-worded provisions in the penal code that are frequently used to persecute domestic critics.
Minh responded that the communist country "respects and promotes" human rights, while it was willing to engage with the US to improve.
In a sign of warming US ties with Hanoi, last year Washington partially lifted a 40-year ban on arms sales to Vietnam.
The move came in the face of growing assertiveness by Beijing in the South China Sea where Hanoi is locked in a longstanding territorial dispute with China over island chains.
On Friday Minh asked the US to fully lift the embargo on lethal weapons sales, saying Vietnam "respected" its role in contributing to peace in the region.
But a senior US state department official told reporters the embargo, imposed after the Vietnam War ended, would not be eased further without concrete progress on rights issues.
The contested South China Sea is a key global shipping route and a major geo-strategic tension point between China and the US.
Earlier Friday, Kerry said resolution of disputes in the waters "should depend on who has the better argument not who has the bigger army", urging all parties to refrain from "provocative acts".
- Trade and TPP -
The one-time presidential hopeful also called for further economic integration between the former enemies on his Hanoi tour.
Bilateral trade has surged from around $450 million in 1995 to more than $36 billion today, even as the two countries work towards concluding the ambitious US-led Trans-Pacific Partnership (TPP) trade deal.
"These aren't just statistics. They're a measure of one of the most remarkable transformations in the history of world affairs," Kerry said.
Labour rights issues -- Vietnam does not allow independent trade unions -- have been a sticking point in the ongoing trade negotiations, which also include Singapore, Malaysia, Japan and other Pacific Rim countries, but not China.
Despite this, Kerry said that the TPP, a key economic priority for the US administration, was close to completion after years of painstaking talks.
"We are hoping very much that over the course of a couple of months, before the end of the year, TPP can be completed."
Kerry, who has said his political activism was inspired by his experiences patrolling waterways in the Mekong Delta during the Vietnam War, said the turn-around in US-Vietnam relations could serve as a model for others.
"The war that took place here half a century ago divided each of our countries and it stemmed from the most profound failure of diplomatic insight and political vision," he said earlier Friday.
The top US diplomat served with the US Navy from 1966 to 1970 as a lieutenant and it was on his return after two tours of duty that he became a fierce campaigner against the war.
His trip has been dogged by domestic US debate over the Iran nuclear deal and on Friday key Democrats in Congress said they would vote against the deal in a blow to President Barack Obama's efforts to sell the measure.
Abandoning the deal "will lead people to put pressure on military action since the United States would have walked away from a diplomatic solution", he said in Hanoi.
"Rejection is not a policy for the future. It does not offer any alternative," he added.